Forging die blocks operate under severe mechanical and thermal conditions. They are subjected to intermittent heating and cooling, high stresses and severe abrasion. The important properties for a steel to be used in forging die blocks are:
1. Good hardenability, since it is normal for a cavity to be resunk several times during the life of a block; PA1 2. Good machinability; the blocks are pre-hardened and have to be machined extensively during their lifetime; PA1 3. Adequate degree of toughness particularly in the centre of the block; PA1 4. Retention of strength and wear resistance at high temperatures.
The properties described in points 1-3 above are in fact desirable characteristics for all heavy forgings.